Error 500 while accesing admin pannel

i was using OJS

After login in while i was accessing admin panel i used to get “HTTP ERROR 500”

in error log file i got fattal error as follows
[27-Jul-2019 15:17:30 UTC] PHP Warning: Declaration of OpenAIREDAO::setOAI(&$oai) should be compatible with PKPOAIDAO::setOAI($oai) in /home/rubatosi/public_html/journals/plugins/generic/openAIRE/ on line 0

[27-Jul-2019 15:17:31 UTC] PHP Fatal error: Uncaught → Smarty Compiler: Syntax error in template “core:core:commonheaderHead.tpl” on line 20 “LHCChatOptions.opt = {widget_height:340,widget_width:300,popup_height:520,popup_width:500};” - Unexpected “:”, expected one of: “}” ←
thrown in /home/rubatosi/public_html/journals/lib/pkp/lib/vendor/smarty/smarty/libs/sysplugins/smarty_internal_templatecompilerbase.php on line 20

how to rectify it please let me know

Hi @salman20054,

Are you editing the Smarty templates? If so, you probably need to properly escape { and } characters, by using {ldelim} or {rdelim} or enclosing the whole thing in {literal} tags. For more on Smarty syntax, see

Alec Smecher
Public Knowledge Project Team

just for a try, i had inserted the code in line 20 in headerhead.tpl,
after having a try in front end i opened the file to remove the code/alter the code but the code which i was pasted is no longer available in it.

how can i rectify this error.

issue had been solved by replacing old back files.